The so-called lyman-α photon is the lowest energy photon in the lyman series of hydrogen and results from an electron transitioning from the n = 2 to the n = 1 energy level. determine the energy in ev and the wavelength in nm of a lyman-α photon. (a) the energy in ev
(b)the wavelength in nm

a) 10.2 eV

b) 122 nm

Explanation:

a) First we must obtain the energy for each of the states, which is given by the following formula:

So, we have:

Now we find the energy that the electron loses when it falls from state 2 to state 1, this is the energy carried away by the emitted photon.

b) Using the Planck – Einstein relation, we can calculate the wavelength of the photon:

Where E is the photon energy, h the Planck constant and   the frequency.

Recall that , Rewriting for :

Recall that , So:

an energy transformation flow diagram is shown

where is it ?